add/remove     add/remove
    Eth Flow-ID    IP Flow-ID
        |             |
        v             v
     +-----------------------------------------------------------+
     |      |      |      |                                      |
     | Eth  | MPLS |  IP  |     Application data                 |
     |      |      |      |                                      |
     +-----------------------------------------------------------+
               ^
               |
           add/remove
          MPLS Flow-ID